I'm probably ruining my pitch, but as a secondary villain, I wouldn't mind seeing a cyber-mischief causing hacker who goes by the tag Mxyzptlk be a force of mayhem that Clark & Lois have to solve.. (and of course, I'm basing this on the notion that Goyer/Nolan would likely dump the angle of the 5th dimension imp with reality-warping magic). Multiple disasters could be caused which would prompt Superman to rescue various sets of people, potentially worldwide. Computer terror/crime is the closest "real-world" application of "magic" to be able to affect distant parts of the world with but a keystroke.

We've seen in other films (Die Hard 4 comes to mind) at the type of (action movie) disruptions that can take place with a dedicated hacker (or a team of them-- maybe one is M, another ix X, Y, Z, etc.)

Assuming that the producers would want to go with a "traditional" Mxy stature, then maybe he can be played by Peter Dinklage..

That sounds more like a Marvel/Disney movie, than it would fit into Snyder's world. I think they go for somebody more physical, more real.